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(NoModeL) G; A. PORTER.

STEAM BOILER.

Patented MM. 1883.

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U ITED STATES ATENT GEORGE A. PORTER, OF SYRACUSE, NEW YORK.

STEAM-BOILER.

SPECIFICATION formingpart of Letters Patent No. 273,357, dated March 6, 1883,

Application filed January 6,'1 883. (No model.)

I 0 all whom it may concern:

Be it known that I, GEORGE A. PORTER, of Syracuse, in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Steam-Boilers, of which the following, taken inconnection with the accompanying drawings, is a full, clear, and exact description.

This invention relates to that class of steamboilers which are termed return-flue boilers. In such boilers the products of combustion pass from the furnace or fire-box through a main direct flue to the so-called combustionchamber at the rear end of the boiler, and thence back through return-fines in the boiler tothe smoke-box and stack on the front end The combustion chamber of said boiler, especially when straw and other light fuel is used, is usually subjected to such intense heat as to necessitate the protection of its shell by a water-jacket surrounding the same. It is this water-jacket to which my invention has special reference, the object of the invention being to simplify and cheapen the construction, and at the same time give it a form which shall afford the maximum stability, and dispense with the use of stay-bolts, heretofore employed for sustaining the crownsheet of the combustion-chamber.

The invention consists in the combination of the boiler-shell, terminating with a straight cylindrical end, the flue-sheet, of circular form, of smaller diameter than the interior of the boiler-shell and concentric therewith, and a cylindrical supplemental shell extended from said flue-sheet, and formed with a flare, and with an enlarged cylindrical end, which latter is fitted and secured to theinterior of the boiler-shell, all as hereinafter more fully explained, and specifically set forth in the claim.

The invention is fully illustrated in the ac companying drawings, wherein Figure 1 is a longitudinal vertical section of a steam-boiler provided with my improvement; and Fig.2 is a vertical transverse section of the same, taken on line or a; in Fig. 1.

Similar letters of reference indicate corresponding parts.

A represents the shell of a return-flue boiler; B, the furnace or fire-box; (J, the combustion-chamber, communicating with the fire-box by the large direct flue D, extended longitudinally through the water-space of the boiler; and E denotes the smoke-box, receiving the products of combustion from the combustionchamber 0, through return-fines a a, extended main boilershell A, I form with a straight cylindrical extension,A, beyond the flue-sheet d. Theflue-sheet I make circular in form-and of a sufficiently smaller diameter than the interior of the boiler-shell, so that when placed in its requisite concentric position in said shell it will be isolated therefrom, and with an opening around the edge of the flue-sheet. The edge of the flue-sheet is formed with the usual outward flange, e, and onto the exterior of this flange 1 lap and rivet a supplemental shell,f, which is of cylindrical form, and is extended to the end of the main shell-extension, A, and joined therewith by a flare, g, of the-shell f, terminating with a diametrically enlarged straight end, h, fitted to the interior of the extension A, and riveted thereto in the usual manner. By this construction I obtain the de sired steam and water jacket Z1 around the combustion'chamber (J in a very simple and comparatively inexpensive manner, forming only two joints and seams of rivets, which are convenient of access for calking and tightening; also obviating the extra expense and labor of flanging, curving, or otherwise distorting the boiler-shell, and dispensing with the stay-bolts hitherto employed for sustaining the flatcrownsheet of other combustion-chambers.

Having described myinventiou, what Iclaim as new, and desire to secure by Letters Patent, 1s-

In a straw-burning horizontal return-flue boiler, the combination of the boiler-shell A, formed with the straight cylindrical extension A beyond the rear flue-sheet, the direct flue D, return-fines a a, the circular flue-sheet d, of smaller diameter than and concentric with the interior of the boiler-shell, and provided with the outward flange e, the cylindrical supplemy name and aflixed my seal, in thepresenceof mental shellfilapped onto flange e, and termitwo attesting witnesses, at Syracuse, in the ro nating with the flare g and circumferentiallycounty ofOnondaga, in the State of New York, enlarged straight end h, and joined by thelatthis 2d day of January, 1883.

ter to the interiorof the endot' the boiler-shell, GEORGE A. PORTER. [L. s] all constructed and combined substantially in Witnesses: the manner described and shown. F. H. GIBBS,

In testimony whereof I have hereunto signed (J. RAYMOND. 

